The general expectation going into the 2012 was that the Broncos defense would continue the improvement trend that started in 2011. Last year I did a post prior to the season talking about what we could realistically expect in terms of the improvement of the defense from the 2011 to the 2012 season. Here's the link

realistic defensive improvements

I was curious to see how we fared relative to my predictions and also to put our defensive improvement into historical context. I you just looked at the previous post you saw that I looked at the greatest improvements year-to-year for defenses in the league in the past decade. So here are the results

The stats that I focused in the first post were:

points per game

yards per game

yards per play

yards per point

forced turnovers

QB rating against

sacks

via cbssports.com

Points per game

The Broncos improved from 24.4 down to 18.6. The 5.8 ppg decrease was good, but not one of the top ten in the past decade. The two-year improvement of 11.3 ppg, however, was the best two year improvement in the past decade. The next closest was the Titans from 06-07-08 whose defense shaved 10.4 ppg off. To put it in perspective, a double digit improvement in ppg over three seasons has only happened three times in the past decade. The other team to accomplish the feat was the 2012 Seahawks, whose decrease was 10.1 ppg. The only other team to come close was Lions from 08-09-10 whose ppg went down 9.2.

The conclusion here is that while many teams have been able to have a good improvement one year to the next, it is rare to have continued improvement in two successive years. It is even rarer to have significant improvement in three successive years. Two caveats here: 1. The Broncos were starting from one of the worst defenses in the history of the league in 2010 - so there was plenty of room for improvement. 2. The odds of improving three years in a row are slim. It has only happened three times in the past decade:

The Bears improved in three successive seasons 02-03, 03-04 and 04-05 decreasing their points allowed by 11.1.

The Vikings from 04-05, 05-06 and 06-07 improved by 5.3 ppg.

The Bengals are the only instance of a team improving in 4 straight seasons. Starting with 02-03 they improved 4.5, 0.8, 1.3 and 1.2 ppg each year. Their total improvement was only 7.8 which is smaller than some teams have accomplished from one season to the next (see Houston 10-11).

I would say that the Broncos greatly exceeded expectations in terms of points allowed.

Yards per game

The Broncos shaved 67 yards per game off of the 2011 total. This was not even the biggest improvement in the league though. The Packers were able to surrender an astounding 74.8 yards per game less this year than in 2011. That 75.8 yard per game reduction was the 4th best in the past decade in the NFL. The Broncos 67 yard reduction ranks 7th in the past decade. The best in the past decade was the 2011 Houston team that shaved 91.2 yard per game off of their 2010 total.

Again the Broncos greatly exceeded expectations for yards allowed. Remember that even a modest reduction in yards allowed per game (25 yards) only happened 23% of the time in the past decade in the NFL.

Yards per play

This is the one the really blew me away. The Broncos were tied for the league league in yards per play. The Broncos were able to reduce their yards per play (ypp) by 0.8. This is after reducing their ypp by 0.5 in the previous year - more on this later. Three teams had big decreases in ypp this year relative to last. The Packers gave up 1.1 fewer yards per play in 2012 than in 2011. However, they had a big increase in ypp from 2010-2011 (1.2), so they are right about where the started. The Panthers also made tremendous leaps in 2012 improving by 0.9 ypp relative to 2011, but it is the same situation as the Packers. The Panthers gave up 1.1 more ypp in 2011 than in 2010.

The Broncos 1.3 ypp improvement over two seasons is great, but not mind-blowing. Houston and Jax decreased their ypp in 2011 by 1.2 relative to 2010. What is mind-blowing is that in the last decade it is the best year-over-year change in the league. The next best is the Titans who lowered their ypp by 1.0 (0.8 in 06-07 and 0.2 in 07-08). Teams have been able to improve in two consecutive years 18 times in the past decade (18/320 = 5.6%) so it is fairly rare. There have only been two instances of teams improving in three straight season, so it is extremely rare . I would love to see us improve again though. There have been teams recently who gave up significantly fewer than the 4.6 ypp allowed by the Broncos and Steelers this season. The 08 Steelers allowed only 3.9 ypp. The 09 Jets only allowed 4.2 ypp. Our D can get better than 4.6 ypp, but it will not be easy and if we do so we will move into the conversation for top defenses in the past decade.

Yards per point

The Broncos did get better in yards per point (by 1.5) but this number is not dramatic and was only slightly above average for the year. This was due in large part to some of the TDs we surrendered off of turnovers.

If anything, I would say that the Broncos did not meet expectations here.

Forced Turnovers

The Broncos forced five more turnovers in 2012 than they did in 2011 (10 defensive fumble recoveries and 16 INTs). This change, while improvement, is nothing special. The Bears forced 25 more turnovers this year than in 2011 (and still missed the playoffs). The SB loser 49ers forced 21 FEWER turnovers than in 2011. The 24 total turnovers forced by the Broncos were 16th in the league. Our offense turned the ball over 25 times. Neither the defense nor the offense lived up the to the preseason expectations in terms of turnovers. I think that the defense will actually generate more turnovers next season for two reasons: I believe we will draft a DT who is a better pass rusher than all on the current roster except Wolfe and I think that some of the dropped INTs from 2012 will turn into actual INTs in 2013. Additionally the hoped for pressure up the middle coupled with VonDoom from the edges should force more bad throws - leading to more picks.

via cache.daylife.com

QB rating against

The Broncos in 2011 were below average in terms of opposing AB rating against. In 2012 the Broncos were in the top 10 in terms of QB rating against (9th) with a value of 79.4. This is a fairly dramatic improvement over the previous year, but it was only the 3rd best improvement in the league (the Colts and Vikings had greater improvements). In terms of historical perspective our 13.7 improvement was not even close to the top 10 improvements of the past decade. It is fairly common for teams to show year over year over year improvement in QB rating against. In fact the Packers have improved each season for the past four - admittedly they had the worse pass D in the league in 2008. The league leaders in this stat in 2012 were the Cardinals (71.2) followed very closely by the Bears. You'll note that neither team made the playoffs.

via media.knoxnews.com

Sacks

The Broncos D was tied for the league league in sacks this season. The improvement of 12 total sacks is somewhat large (particularly when you consider that the Jags had 20 total sacks this season), but is again not close to the top ten in terms of single season increases in sacks. The greatest single single increase in sacks over the past decade actually belongs to the 2009 Browns (+23). The Broncos improvement in 2011 (+18) is tied for 6th best improvement in the past decade.

The Broncos were 10th in sacks in 2011, so an improvement to #1(tie) is as good as you can hope for. It's fair to say that the Broncos exceeded expectations in terms of improvement in this department. The highest sack total for a team in the past decade was 61 by the 06 Chargers (the Ravens had 60 that year). So it is not unreasonable to think that the Broncos could improve upon the 50 sacks from this season. The general trend in the NFL over the past decade is that the total number of sacks has been roughly constant (the low was 1036 in 2008 with the high being 1196 in 2004). There have been an average of 1140 sacks per year in the past decade (plus or minus 51). The trend over the past decade is roughly 4 fewer sacks per year than the year before.

via extras.mnginteractive.com

3rd Down conversion % allowed

I did not mention this stat in the intro, but I decided that I had to bring it up (particularly since I was tracking it all year). The Broncos lead the league in this statistic in 2012. You could argue that this stat is actually more important than everything except points allowed. The Broncos improved from 34% to 31%. While this was good, it is far from the top ten in terms of year over year improvement, partially because the Broncos had improved by 4% in 2011 relative to 2010. There have been quite a few double digit improvements in the past decade, in fact the Broncos own the single biggest in the past decade with 14% in 2003 relative to 2002. In a single season the Broncos went from allowing 44 conversion to allowing a paltry 30% conversion. Their is precedent for allowing less than the 31% that the Broncos allowed to lead the league in 2012. The 2003 Titans only allowed 28% conversion on 3rd downs, however, the instance of teams allowing less than 31% conversion in the past decade is fairly low. So it might not be realistic to expect any more improvement in this stat. There are three instances of a team improving in this stat for three straight years in the past decade, so it can be done, but the odds are strongly against it (DAL 07-09, DET 09-11 and SF 07-09).

It is safe to say that the Broncos defense greatly exceeded almost everyone's expectations in 2012. I hope you enjoyed this. Go Broncos!